yep. Although at 121 to 123 it won't hurt your 400 to run it on the wall as it's designed to run120V without problems. I have 124 to 126 at my house and only one of my consoles is running a buck transformer and that's a 12v bucking transformer as the '51 Coronet was designed for 110. Everything else runs off the wall. But then again I keep an eye on my heater voltages and I'm not overly anal with respect to the wall voltages like some guys are. I've been running tubes in various gear sincei was a kid and still have a Hammarlund SP-600 shortwave military transceiver, my dad gave me when I was 13 from Navy Surplus. It needed some Main Filter caps and a tune up, which when compared to a 400, the 400 is childs play. I still break it out and run it straight from the wall.